Generally, an air handler is a device that heats air by exchanging heat between a heat medium provided from a heat source and outside air at an air conditioner, thereby supplying the heated air into an internal space for heating. When cooling the internal space, on the other hand, the device cools air by exchanging heat between a cooled heat medium and outside air, and supplies the cooled air into the internal space.
While various heat sources can be used as a heat source for an air handler during heating, an air handler system utilizing a water heater as a heat source is proposed. In the Korean Laid-Open Patent Publication No. 10-2011-0121561 (Method for Improving Performance of Heating and Cooling System and Heating and Cooling System Using The Method, Publication date: Nov. 7, 2011), a system, which circulates and receives heated water from a water heater, and heats air by drawing air through a blower to supply the heated air into an internal space, is described.
Although the patent was for improving the performance of the air handler system by controlling a discharge rate of air, some conditions when using a water heater as a heat source were not considered.
For example, when hot water is heated by a water heater to heat air, and the hot water is used while the hot water is used in heating, there is a problem in that a hot water temperature and a heating temperature could not reach a set temperature. In particular, when the hot water temperature cannot reach the set temperature while using the hot water, a user can immediately feel this and may dissatisfy the performance of the product.